WO2003076282A1

WO2003076282A1 - Can

Info

Publication number: WO2003076282A1
Application number: PCT/BR2003/000036
Authority: WO
Inventors: Antonio Carlos Teixeira Alvares; Antonio Roberto Sene
Original assignee: Brasilata SA Embalagens Metalicas
Current assignee: Brasilata SA Embalagens Metalicas
Priority date: 2002-03-12
Filing date: 2003-03-12
Publication date: 2003-09-18
Anticipated expiration: 2004-09-12
Also published as: AR038912A1; AU2003212130A1

Abstract

A can comprising a tubular lateral wall (10) with a circular or polygonal contour and having end edges onto which are respectively double seamed an upper wall (11) and a bottom wall (12). The tubular lateral wall (10) has an upper portion and, optionally, a lower portion in the cylindrical cans, which portions are somewhat axially spaced from the adjacent double seamed regions and each being provided with a plurality of grooves (17) defining weakening zones that extend in respective circumferential alignments, said grooves (17) being usually continuous but which may be limited to the longitudinal rounded vertices of the cans having a polygonal cross section.

Description

CAN Field of the Invention

The present invention refers to a new constructive arrangement applied to cans comprising a lateral wall which has a cylindrical or a polygonal contour, said polygonal contour usually being square or rectangular, to the end edges of said lateral wall being double seamed a bottom wall and an upper wall, which can be annular with a large discharge opening closed by a press-fit lid, or in a single closed piece provided with a small discharge opening. The invention allows the present can to be used to contain dangerous goods in volumes ranging from about 1 to 12 liters. Background of the Invention It is well known in the prior art a can construction having a cylindrical lateral wall and according to which the upper annular wall of the can comprises a substantially circular large opening, which is internally defined in relation to a closure seat formed in the upper wall along the periphery of the opening and incorporating a pending peripheral wall inside which a press-fit lid is seated. In certain constructions, the pending peripheral wall, whose upper edge defines the closure seat, operates only as a sealing and retaining element, merely by friction, in relation to a lateral wall of the press- fit lid to be fitted inside said pending peripheral wall of the annular upper wall of the can. In an also known construction, which is object of the Brazilian patent PI 9408643-5 of the same applicant, the lower portion of the pending peripheral wall is curved inwardly and upwardly from the can opening, to a point in which the free end edge thereof reaches a position adjacent to said pending peripheral wall. In this prior construction of the same applicant, the pending peripheral wall which surrounds and defines the discharge opening incorporates a continuous tubular rim of circular cross section disposed in a plane which is lower than the plane of the closure seat, that is, the upper edge of the pending peripheral wall .

Moreover, according to said patented prior solution, a lid is provided having a peripheral edge generally defined by a tubular rim obtained by being bent outwardly and downwardly and from which is downwardly projected a circular lateral wall provided with a peripheral recess having an approximately semicircular cross section and which is dimensioned to be fitted around the continuous tubular rim when the lid is seated onto the discharge opening of the can. The peripheral edge is seated onto the closure seat when the lid is seated onto the discharge opening. While resulting in an excellent axial locking of the lid in the closed position and further eliminating risks of causing injury during handling and contamination of the stored product by contact with non-varnished parts of the can foil, said prior art solution, object of the Brazilian patent PI 9408643-5 still presents the need for an increased structural resistance in order to meet the specifications required for containers of dangerous goods . As it is known, cans for dangerous goods have to resist a certain level of internal pressure for a determined period of time without suffering a structural deformation that impairs the tightness of the can and the seating of the press-fit lid in the closure seat. In this regard, the constructive solution object of the Brazilian patent PI 9408643-5, optionally associated with the construction proposed for the annular upper wall object of the Brazilian patent PI 0006493-9 of the same applicant, allows maintaining the integrity of the can when subjected to the limit pressure conditions required for the container to be certified as suitable for containing dangerous goods .

On the other hand, while said previous solutions guarantee an adequate retention of the lid in the closure seat in the pressure test conditions for dangerous goods, they do not guarantee the integrity of the closure seat when the can is subjected to a free fall from the test height against a rigid surface, with the lid facing down and at an angle of about 45° from the vertical axis. In the type of fall mentioned above, the upper peripheral region of the can, to which is double seamed the annular upper wall, is submitted to a deformation or "inward mashing", which may deform the closure seat to a level sufficient to destroy the tightness of the can, even if this deformation is not sufficient for expelling the lid.

Said destructive deformation of the closure seat greatly results from the higher resistance to deformation by axial forces and the lower resistance to deformation by radial forces to which the lateral wall region of the can, adjacent to the impact region is subjected in the free fall test in an inclined position.

Depending on the characteristics of the foil utilized in the manufacture of the can, it is also possible to have a deformation of the double seam, in the impact region, which is sufficient to impair the perfect tightness of the can. The problem of loss of tightness by excessive deformation of the double seam in the impact area may occur either in the double seam of the upper wall, when the can falls in an inverted position, or in the double seam of the bottom wall when the can falls in an inclined but not inverted position. The drawbacks mentioned to this point may be particularly associated to the 1 gallon cylindrical cans , commonly used in the market .

It has been also observed that cans with a polygonal cross section, usually square or rectangular, having a storage capacity of 9 and 5 liters, respectively, and having a single-piece upper wall and being optionally provided with a respective lid, are also vulnerable to the occurrence of loss of tightness by excessive deformation of the double seams when subjected to an impact caused by the can falling in an inclined position. In the cans having a polygonal cross section, the regions of the double seams that are more vulnerable to the loss of tightness are those which define the rounded vertices of the section having a polygonal contour of the upper and lower walls, which vertices define the upper and lower ends of the respective rounded longitudinal edges of the can.

When a can with a polygonal cross section of the type considered herein falls in an inclined position, inverted or not, in such a way that a vertex of one of the upper or lower walls contacts the impact surface, the double seam region which defines this vertex may be subjected to an excessive deformation of the can in said deformed double seam region. While the problem of loss of tightness is more common in the vertex region when the vertices define the impact region in the can fall, this problem can also occur in other extensions of straight or curved double seam, such as in the cylindrical cans.

In the case of cans in which the high deformation of the peripheral end edges defined by the double seams does not have a significant influence over the integrity of the lid seat and over the retention and tightness of said lid, the maintenance of the perfect tightness in the double seam regions is of great importance, particularly in the case of cans utilized for containing products which are considered dangerous .

The known solutions for minimizing the problem of deformation in the closure seat and in the double seam regions submitted to impact when the can, fully loaded, is subjected to the free fall test conditions, require the provision of auxiliary protective devices attached to the can and which considerably increase the cost of the container. Object of the Invention

It is the object of the present invention to provide a can of the type considered herein, presenting a simple construction which resists to the conditions required for containing dangerous goods, in terms of internal pressure variations and in terms of resistance to impacts resulting from free fall, but maintaining the tightness of the container. Summary of the Invention

The object mentioned above is achieved through the provision of a can comprising a tubular lateral wall with a circular or polygonal contour and having end edges onto which are double seamed a bottom wall and an upper wall, respectively. In the cylindrical cans, the upper wall may be formed by a peripheral structural ring defining, internally, a large discharge opening, onto which is seated a press-fit lid.

According to the invention, the tubular lateral wall of the can has an upper portion which is slightly axially spaced from the region where it is double seamed to the upper wall and presents a height of about 1.5 to 3.0 cm provided with a plurality of grooves which extend in respective mutually parallel circumferential alignments, along at least part of the contour of the tubular lateral wall .

Still, according to the invention, the tubular lateral wall may be provided with another plurality of grooves, which may be identical or similar to the first and located in a lower portion of the tubular lateral wall, being slightly axially spaced from the region of double seam to the bottom wall. The construction defined above forms a weakening zone of the tubular lateral wall, which zone is dimensioned to absorb, through a localized plastic deformation, the energy resulting from the impact of the full can in an inclined free fall against a rigid surface. The circumferential grooves make the respective tubular lateral wall region adjacent to the impact point to be more easily deformable than the adjacent upper wall region, thus protecting the double seam regions and the inner peripheral portion of the upper wall when the can falls in an inclined and inverted position, minimizing the deformations on the annular upper wall and thereby maintaining the closure integrity of the lid.

The present invention, which is a development that may be associated to the axial locking of the recloseable press-fit lid object of the Brazilian patent PI 9408643-5 of the same applicant, allows obtaining a can of simple construction and reduced cost, which is perfectly suited to the international requirements for the transportation of dangerous goods. Brief Description of the Drawings

The invention will be described below with reference to the attached drawings, in which: Figure 1 is a diametrical cross sectional view of a cylindrical can having the upper wall in the form of a structural ring defining a large discharge opening in which is seated a press-fit lid, said can being provided with only one plurality of grooves, according to one embodiment of the invention;

Figure 2 is a view similar to that of Figure 1, but illustrating a can having two pluralities of grooves defining two weakening zones of the tubular lateral wall;

Figure 3 is a diametrical cross-sectional view of the can of Figure 1, after being subjected to an inverted and inclined free fall in a common test procedure applied to containers for dangerous goods; Figure 4 is a view similar to that defined for Figure 1, but illustrating the can with the plastic deformation after being subjected to a free fall; Figure 5 is an enlarged detailed view of Figure 1, illustrating part of the upper end edge of the can and of the grooved zone;

Figure 6 is an enlarged detailed view of Figure 3, illustrating part of the deformed upper end edge of the can and of the grooved zone;

Figure 7 is a perspective view of a can having a rectangular cross section provided with two weakening zones on the tubular lateral wall, close to the double seam regions of the bottom and upper walls. Description of the Illustrated Embodiments In the embodiment illustrated in Figures 1-6 of the attached drawings, the present can comprises a tubular lateral wall 10 of circular contour, and an upper wall 11 in the form of a structural ring, an outer peripheral portion 11a which is conventionally double seamed to an end edge of the lateral wall 10; a median portion lib of a larger radial extension; and an inner peripheral portion lie to which is incorporated a pending peripheral wall 14 that defines a discharge opening A.

The illustrated can further comprises a bottom wall 12 that is peripherally and conventionally double seamed to an opposite end edge of the tubular lateral wall 10.

In the embodiment illustrated in Figures 1-6, the upper wall 11 has its median portion lib and inner peripheral portion lie usually contained in the same plane, which is slightly raised in relation to the outer peripheral portion 11a, leading to a corresponding gain in the volumetric capacity of the can. It should be also understood that the upper wall 11 may be formed with its outer peripheral portion 11a, median peripheral portion lib, and inner peripheral portion lie entirely contained in a single plane extending from the lateral wall of the can to the region where the closure seat 13 is defined and wherefrom projects the pending peripheral wall 14, having a lower portion curved to the inside of the discharge opening A and upwardly, until the free edge thereof reaches a position adjacent to said pending peripheral wall 14. In this prior construction of the applicant, the pending peripheral wall 14, which surrounds and defines the opening A, incorporates a continuous tubular rim 16, of circular cross section, disposed in a plane which is lower than the plane of the closure seat 13.

It should be also understood that the upper wall 11 may present its median portion lib provided with an upwardly projecting extension to be located in a slightly raised plane in relation to the outer peripheral portion 11a, which has a generally reduced radial extension and which is double seamed to the tubular lateral wall 10 of the can.

Still, according to the embodiment illustrated in Figures 1-6, a lid 20 is provided having a peripheral edge 21, which is generally defined by a tubular rim obtained by being outwardly and downwardly bent and from which downwardly projects a peripheral lateral wall 22 provided with a peripheral recess 23 having an approximately semicircular cross section and which is dimensioned to be fitted around the continuous tubular rim 16 upon the seating of the lid 20 onto the opening A of the can. The peripheral edge 21 is seated onto the closure seat 13 upon the fitting of the lid 20 onto the opening A. According to the present invention, the tubular lateral wall 10 of the can has an upper portion, adjacent to the double seam region of the upper wall 11, presenting a height of about 1.5 to 3.0 cm, provided with a plurality of grooves 17 which are slightly axially spaced in relation to the region where the lateral wall 10 is double seamed to the upper wall 11 and which are arranged in respective mutually parallel circumferential alignments. The provision of a plurality of grooves 17 on said tubular lateral wall 10 allows minimizing the deformation forces acting on the upper double seam region and on the region of the upper wall 11 which defines the closure seat 13 when the can falls in an inclined and inverted position, that is, with the lid facing down. In these cylindrical cans provided with a large discharge opening closed by a press-fit lid, the provision of the plurality of grooves 17 close to the upper double seam region has the main function of guaranteeing the tightness of the closure of the lid 20, besides also protecting the adjacent double seam region against excessive deformations due to impacts in the inverted position, preventing the can from losing tightness in the double seam region subjected to impact . As illustrated in Figure 2, the can may have the tubular lateral wall 10 further provided with a lower portion, which is slightly axially spaced from the region where it is double seamed to the bottom wall, and presenting a height of about 1.5 to 3.0 cm, provided with a plurality of grooves 17 arranged in mutually parallel circumferential alignments. The provision of the lower plurality of grooves 17 in an arrangement that is identical or similar to that of the upper plurality of grooves 17, allows protecting the region where the lateral tubular wall 10 is double seamed to the bottom wall 12 against excessive deformations which cause loss of tightness due to a fall of the can. In the cylindrical cans with a large upper discharge opening closed by a press-fit lid, a substantially different design is desired for the two weakening zones of the tubular lateral wall 10, since the lower plurality of grooves 17 has the function of preserving the integrity of the region of double seam to the bottom wall 12, which is integral, while the upper plurality of grooves 17 has the main function of preserving the integrity of the tight seat of the lid onto the upper wall 11 in the form of a structural ring, besides further protecting the adjacent double seam region against destructive deformations of the tightness .

Another aspect to be considered in the cylindrical cans is that the grooves 17 must be disposed in a continuous circumferential arrangement, in order to provide the same structural protection along the entire contour of the can.

The axial spacing of the upper and lower portions of the tubular lateral wall 10 in relation to the adjacent double seam regions is usually of about 3-10 mm, in order to avoid any interference of the grooves 17 with said double seam regions.

The circumferential grooves 17 are radially projected preferably to the inside of the tubular lateral wall 10 and are obtained by deformation of the latter and configured to present a "V" shaped profile, defining the grooves of a grooved region of the lateral wall 10, which becomes a circumferential weakening zone of the tubular lateral wall 10 when the latter is submitted to compressive axial forces . The dimensioning of the grooves 17, the angle of the profile and the number of grooves are determined in function of the level of the axial weakening desired for the respective portion of the tubular lateral wall

10. The grooves 17 are usually in the number of 3-6 and present an angle of profile ranging from about 30° to 60° and a depth somewhat lower than half the maximum width of each groove 17.

With the provision of the grooves 17 and the formation of the axial weakening zones of the tubular lateral wall 10 near the double seam regions of the upper wall

11, when the can has the upper peripheral edge thereof subjected to an impact caused by an inclined and inverted free fall, the component of the axial force applied to the can causes the deformation of the grooved region of the tubular lateral wall 10, through the closing of one or more of the grooves 17. The plastic deformation of the grooved region absorbs the energy from the impact of the can against the rigid surface, producing the deformation of the tubular lateral wall 10 in a region which tends to be spaced from the closure seat 13, allowing the latter to be suited to tightly retain the lid 20, as illustrated in figures 3 , 4 and 5.

It should be further understood that the grooves 17 increase the radial structural resistance of the lateral wall 10, tending to better resist the radial component of the impact force of the fall and thus better preserve the circular contour of the end region of the can being impacted against the rigid surface. The impact energy is mostly absorbed by the axial plastic deformation of the tubular lateral wall 10 in the grooved region thereof and by a corresponding smashing or axial displacement of the outer peripheral portion 11a of the annular upper wall 11 which remains double seamed to the tubular lateral wall 10.

As mentioned before, the grooves 17, by weakening in a localized and predetermined manner the respective upper and lower portions of the tubular lateral wall 10 of the can, avoid the double seam regions subjected to impact from being excessively deformed, assuring the tightness of the fallen can.

Figure 7 shows a can having the tubular lateral wall 10 presenting a polygonal cross section, more specifically a rectangular cross section with rounded vertices.

In these cans of polygonal contour, usually rectangular or square and having rounded longitudinal vertices, the upper wall 11 and bottom wall 12 are usually defined by a single piece foil which is peripherally double seamed to the respective end edge of the tubular lateral wall 10. The upper wall may be further medianly provided with a small discharge opening to be closed by a suitable lid, which may present different constructions. Although these cans do not present the large upper discharge opening to be preserved from deformations caused by impacts on the upper edge of the can, the double seam regions of the upper and bottom walls thereof are more vulnerable to the excessive deformation on the curved extensions which define the profile of the rounded longitudinal vertices. When the can falls in an inclined position and so that the impact occurs against one of the longitudinal vertices, the curved extension of the double seam region subjected to impact tends to be excessively deformed, allowing for the loss of tightness in this extension.

The invention foresees for these cans of polygonal contour the provision of the same cylindrical grooves that operate in the same manner, reducing the destructive forces applied against the vertices of the upper and lower double seam regions. However, considering that the straight extensions of the double seam regions are less vulnerable to impacts by falling, the grooves 17 my be provided only in the extensions of the tubular lateral wall 10 which define the longitudinal corners that are rounded or extended in a continuous circumferential manner along the whole contour of the tubular lateral wall. It should be understood that different modifications in the shape and in the number of circumferential grooves may be made without departing from the scope of the invention defined by the claims which are part of the present application.

Claims

1- A can comprising a tubular lateral wall (10) with a circular or polygonal contour and having end edges onto which are double seamed an upper wall (11) and a bottom wall (12) respectively, characterized in that the tubular lateral wall (10) has an upper portion which is slightly axially spaced from the region where it is double seamed to the upper wall (11) and presents a height of about 1.5 to 3.0 cm provided with a plurality of grooves (17) which extend in respective mutually parallel circumferential alignments, along at least part of the contour of the tubular lateral wall (10) .

2- Can, according to claim 1, characterized in that the tubular lateral wall (10) is provided with a lower portion, slightly axially spaced from the region where it is double seamed to the bottom wall (12) and which presents a height of about 1.5 to 3.0 cm provided with a plurality of grooves (17) which extend in respective mutually parallel circumferential alignments, along at least part of the contour of the tubular lateral wall (10) .

3- Can, according to claim 2, characterized in that said upper and lower portions of the tubular lateral wall (10) are identical and equally spaced from the adjacent double seam regions of the can.

4- Can, according to any one of claims 1, 2 or 3, characterized in that the grooves (17) are axially spaced from about 3-10 mm in relation to the adjacent region where the tubular lateral wall (10) is double seamed to the upper wall (11) and to the bottom wall (12) .

5- Can, according to any one of claims 1, 2 or 3, characterized in that the grooves (17) are obtained by deformation of the tubular lateral wall (10) . 6- Can, according to claim 5, characterized in that the grooves (17) present a "V" shaped profile, each defining a groove of a grooved region of the lateral wall (10) . 7- Can, according to claim 6, characterized in that the grooves (17) present an angle usually ranging from 30° to 60°.

8- Can, according to claim 5, characterized in that the grooves (17) radially project to the inside of the lateral wall (10) .

9- Can, according to claim 1, characterized in that the plurality of grooves (17) comprises 3-6 grooves.

10- Can, according to any one of claims 1 or 2 , characterized in that the upper wall (11) comprises a structural ring of circular contour, presenting an inner peripheral portion (lie) defining a closure seat

(13), and from which projects a pending peripheral wall (14) defining a discharge opening (A) onto which is fitted a peripheral lateral wall (22) of a lid (20) , said pending peripheral wall (14) incorporating a tubular rim (16) to be fitted in a peripheral recess (23) provided in the peripheral lateral wall (22) of the lid (20) .

11- Can, according to any one of claims 1, 2 or 3, characterized in that the grooves (17) are continuous.

12- Can, according to any one of claims 1, 2 or 3, characterized in that the grooves (17) are provided only along convex longitudinal corners of the tubular lateral wall (10) of polygonal contour.